KR102301667B1 - Rubber composition - Google Patents

Abstract

The present invention relates to a rubber composition having excellent abrasion resistance and improved tensile and viscoelastic properties by controlling compatibility between rubber components, and a tire manufactured using the same.

Description

Rubber composition {RUBBER COMPOSITION}

The present invention relates to a rubber composition having excellent abrasion resistance and improved tensile and viscoelastic properties by controlling compatibility between rubber components, and a tire manufactured using the same.

In response to the recent demand for fuel economy reduction in automobiles, it is required to reduce the rolling resistance of tires, and in terms of safety, there is a need for a tire that has excellent wear resistance and tensile properties, and also has adjustment stability typified by wet road resistance. . Accordingly, there is known a method of blending a filler such as silica with a rubber component constituting a tire, particularly a tire tread, to achieve both low rolling resistance and adjustment stability.

For example, in order to reduce the rolling resistance of the tire, there is a method of reducing the hysteresis loss of the vulcanized rubber. As an evaluation index of the vulcanized rubber, rebound elasticity of 50°C to 80°C, tan δ, Goodrich heat generation, etc. are used. . That is, a rubber material having a large rebound elasticity at the above temperature or a small tan δ Goodrich heat generation is preferable.

As a rubber material with a small hysteresis loss, natural rubber, polyisoprene rubber, polybutadiene rubber and the like are known, but these have a problem of low resistance to wet road surfaces. Accordingly, recently, conjugated diene polymers or copolymers such as styrene-butadiene rubber (hereinafter referred to as SBR) or butadiene rubber (hereinafter referred to as BR) have been manufactured by emulsion polymerization or solution polymerization and are used as rubber for tires. . Among them, the greatest advantage of solution polymerization compared to emulsion polymerization is that the content of vinyl structure and styrene content defining rubber properties can be arbitrarily adjusted, and molecular weight and physical properties can be adjusted by coupling or modification. that it can be adjusted. Therefore, it is easy to change the structure of the finally manufactured SBR or BR, and it is possible to reduce the movement of the chain ends by bonding or modifying the chain ends, and to increase the binding force with fillers such as silica or carbon black. It is widely used as a rubber material for

When this solution-polymerized SBR is used as a rubber material for a tire, by increasing the vinyl content in the SBR, the glass transition temperature of the rubber can be increased to control the required physical properties of the tire such as running resistance and braking force, and the glass transition temperature can be lowered. By properly adjusting it, fuel consumption can be reduced. The solution polymerization SBR is prepared using an anionic polymerization initiator, and the chain ends of the formed polymer are bound or modified using various modifiers. For example, U.S. Patent No. 4,397,994 discloses a technique in which an active anion at the chain end of a polymer obtained by polymerizing styrene-butadiene in a non-polar solvent using alkyllithium, a monofunctional initiator, is combined using a binder such as a tin compound. did.

In addition, carbon black and silica are used as reinforcing fillers for tire treads. When silica is used as reinforcing fillers, there are advantages of low hysteresis loss and improved wet road resistance. However, compared to carbon black on the hydrophobic surface, silica on the hydrophilic surface has a low affinity with the rubber component and has a high cohesive property between silicas, so a separate silane coupling agent is used to improve dispersibility or to impart a bond between silica and rubber. need to use Accordingly, a method has been made to introduce a functional group having affinity or reactivity with silica at the end of the rubber molecule, but the effect is not sufficient.

KR 2015-0110668 A US 04397994 A

The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide a rubber composition having excellent wear resistance and improved tensile properties and viscoelastic properties by controlling compatibility between rubber components.

Another object of the present invention is to provide a tire manufactured using the rubber composition.

In order to solve the above problems, the present invention provides 30 parts by weight to 90 parts by weight of a first synthetic rubber with respect to 100 parts by weight of a rubber component comprising a first synthetic rubber and a second synthetic rubber; 10 parts by weight to 70 parts by weight of a second synthetic rubber; and 30 parts by weight to 200 parts by weight of a filler, wherein the first synthetic rubber and the second synthetic rubber have a difference in solubility constant of more than 0.82, and the first synthetic rubber has a styrene content of 38% by weight or more, Provided is a rubber composition that is a modified rubber at both ends having functional groups bonded to both ends.

In addition, there is provided a tire manufactured using the rubber composition.

The rubber composition according to the present invention includes heterogeneous rubber components of the first synthetic rubber and the second synthetic rubber, but between rubbers by selecting and including the first synthetic rubber and the second synthetic rubber so that the solubility constants are different from each other within a specific range. Compatibility can be controlled, and thus, tensile properties and viscoelastic properties can be improved while having excellent wear resistance.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the above-described invention, so that the present invention is limited only to the matters described in those drawings. should not be interpreted.
1 is a graph showing a change in G" (dynamic loss modulus) according to temperature for the rubber compositions of Examples 1 and 2 and Comparative Examples 1 to 3 according to an embodiment of the present invention.
2 is a TEM image (magnification 28K) of a rubber composition according to an embodiment of the present invention, (a) is Comparative Example 1, (b) is Comparative Example 2, (c) is Comparative Example 3, (d) shows the TEM images for Example 1 and (e) Example 2.
3 is a graph showing a change in G" (dynamic loss modulus) according to temperature for the rubber compositions of Example 3 and Comparative Examples 4 to 6 according to an embodiment of the present invention.
4 shows a TEM image (magnification 28K) of a rubber composition according to an embodiment of the present invention, (a) is Comparative Example 4, (b) is Comparative Example 5, (c) is Comparative Example 6 and (d) shows the TEM image for Example 3.

Hereinafter, the present invention will be described in more detail to help the understanding of the present invention.

The terms or words used in the description and claims of the present invention should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

The term 'solubility parameter (δ)' used in the present invention indicates a characteristic value of a substance that is a measure of mixing of substances, and a known solubility constant calculation formula (RUBER CHEMISTRY AND TECHNOLOGY: November 1996, Vol. 69, No. 5, pp. 769-780) was calculated according to Equation 1 below.

[Equation 1]

δ = 17.17 + 0.0272 (% by weight of styrene) -0.0069 (% by weight of vinyl)

The present invention provides a rubber composition having excellent wear resistance and improved tensile properties and viscoelastic properties.

The rubber composition according to an embodiment of the present invention comprises 30 parts by weight to 90 parts by weight of the first synthetic rubber based on 100 parts by weight of the rubber component including the first synthetic rubber and the second synthetic rubber; 10 parts by weight to 70 parts by weight of a second synthetic rubber; and 30 parts by weight to 200 parts by weight of a filler, wherein the first synthetic rubber and the second synthetic rubber have a difference in solubility constant of more than 0.82, and the first synthetic rubber has a styrene content of 38% by weight or more, It is characterized in that both ends are modified rubbers in which functional groups are bonded to both ends.

Specifically, the first synthetic rubber and the second synthetic rubber may have different solubility constants of greater than 0.82 and less than or equal to 1.05.

The rubber composition according to an embodiment of the present invention includes heterogeneous rubber components of the first synthetic rubber and the second synthetic rubber, but the first synthetic rubber and the second synthetic rubber are selected so that the solubility constants are different from each other within a specific range. By including it, compatibility between the rubber components can be controlled, and the physical properties of each of the first synthetic rubber and the second synthetic rubber can be simultaneously expressed. .

Hereinafter, each component included in the rubber composition according to an embodiment of the present invention will be described in detail.

first synthetic rubber

In one embodiment of the present invention, the first synthetic rubber may be a solution-polymerized conjugated diene-based rubber, and specifically, the first synthetic rubber may be a modified rubber at both ends in which functional groups are bonded to both ends.

Specifically, the first synthetic rubber is a solution-polymerized conjugated diene-based rubber, wherein the solution-polymerized conjugated diene-based rubber includes a repeating unit derived from an aromatic vinyl-based monomer and a repeating unit derived from a conjugated diene-based monomer, and functional groups are bonded to both ends The styrene content may be 38% by weight or more, more specifically, the styrene content may be 38% by weight or more, and 55% by weight or less, and more specifically, the styrene content is 38% by weight or more, 45% by weight or more. % or less. When the solution-polymerized conjugated diene-based rubber has the styrene content, rolling resistance, wet road resistance, and low fuel efficiency are excellent.

In addition, the solution-polymerized conjugated diene-based rubber may include extender oil, and in this case, the solution-polymerized conjugated diene-based rubber may have an extender oil content of greater than 0 wt% and 37.5 wt% or less.

In addition, the solution polymerization conjugated diene-based rubber may have a vinyl content of 10% by weight or more, 10% by weight to 40% by weight, or 20% by weight to 40% by weight, and within this range, the glass transition temperature can be adjusted in an appropriate range. It has excellent rolling resistance, wet road resistance and low fuel efficiency. Here, the vinyl content means the content of the 1,2-added conjugated diene-based monomer, not the 1,4-added, based on 100% by weight of the conjugated diene-based copolymer consisting of a monomer having a vinyl group and an aromatic vinyl-based monomer. can

In addition, the functional group may be an amine group and an aminoalkoxysilane group, for example, in the solution-polymerized conjugated diene rubber, an amine group or an aminoalkoxysilane group is bonded to both terminals, or an amine group is bonded to one terminal and the other An aminoalkoxysilane group may be bonded to the terminal.

In addition, the solution-polymerized conjugated diene-based rubber may have a number average molecular weight (Mn) of 20,000 g/mol to 800,000 g/mol, 100,000 g/mol to 550,000 g/mol, or 150,000 g/mol to 500,000 g/mol, and , a weight average molecular weight (Mw) of 40,000 g/mol to 2,000,000 g/mol, 150,000 g/mol to 900,000 g/mol, or 200,000 g/mol to 800,000 g/mol, within which rolling resistance and wet It has an excellent effect on road surface resistance. As another example, the solution-polymerized conjugated diene-based rubber may have a molecular weight distribution (Mw/Mn) of 1.0 to 4.0, 1.1 to 3.5, or 1.3 to 3.0, and within this range, the physical property balance between properties is excellent.

Here, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are polystyrene equivalent molecular weights analyzed by gel permeation chromatography (GPC), respectively, and the molecular weight distribution (Mw / Mn) is also called polydispersity, It was calculated as the ratio (Mw/Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn).

As another example, the solution-polymerized conjugated diene-based rubber may have a Mooney viscosity of 40 to 120, or 50 to 100 at 100° C., and has excellent processability and productivity within this range. In this case, the solution-polymerized conjugated diene-based rubber may not contain extender oil.

Here, the Mooney viscosity was measured using a Mooney viscometer, for example, a Large Rotor of MV2000E (ALPHA Technologies) at 100° C. and 140° C., and a rotor speed of 2±0.02 rpm. Specifically, after leaving the polymer at room temperature (23±5° C.) for more than 30 minutes, 27±3 g was collected, filled in the die cavity, and measured while applying a torque by operating a platen.

The term 'recurring unit derived' used in the present invention may indicate a component, structure, or material itself derived from a certain material. For example, the repeating unit derived from the conjugated diene-based monomer is a repeating unit formed during polymerization of the conjugated diene-based monomer. may mean, and the repeating unit derived from the aromatic vinyl monomer means a repeating unit formed during polymerization of the aromatic vinyl monomer.

On the other hand, the solution polymerization conjugated diene-based rubber according to an embodiment of the present invention is prepared by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent containing a modification initiator, for example, to prepare an active polymer to which an organometal is bonded. and reacting the prepared active polymer with a modifier.

The hydrocarbon solvent is not particularly limited, but may be, for example, at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene and xylene.

The conjugated diene-based monomer is not particularly limited, for example, 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl -1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene or 2,4-hexadiene; Specifically, it may be 1,3-butadiene.

The aromatic vinyl monomer is not particularly limited, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p- Methylphenyl)styrene and 1-vinyl-5-hexylnaphthalene may be used, and specifically, styrene may be used.

The modification initiator may be a compound prepared by reacting the organometallic compound with an amine group-containing compound.

The organometallic compound is, for example, methyllithium, ethyllithium, propyllithium, n-butyllithium, s-butyllithium, t-butyllithium, hexyllithium, n-decyllithium, t-octyllithium, phenyllithium, 1-naph Tyllithium, n-eicosyllithium, 4-butylphenyllithium, 4-tolylllithium, cyclohexyllithium, 3,5-di-n-heptylcyclohexyllithium, 4-cyclopentyllithium, naphthyl sodium, naphthyl potassium , lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate, lithium amide, sodium amide, potassium amide and lithium isopropylamide. The compound may be, for example, a compound represented by Formula 1 below.

[Formula 1]

In Formula 1,

R ₁ to R ₃ are each independently hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; A heteroalkyl group having 1 to 30 carbon atoms, a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; or a heterocyclic group having 3 to 30 carbon atoms, and R ₄ is a single bond; an alkylene group having 1 to 20 carbon atoms that is unsubstituted or substituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms that is unsubstituted or substituted with a substituent; or an arylene group having 5 to 20 carbon atoms substituted or unsubstituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms, and R ₅ is an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; a heterocyclic group having 3 to 30 carbon atoms; or a functional group represented by Formula 1a or Formula 1b, n is an integer of 1 to 5 _{, at least one of R 5} is a functional group represented by Formula 1a or Formula 1b, and when n is an integer of 2 to 5, a plurality of R ₅ may be the same as or different from each other,

[Formula 1a]

In Formula 1a, R ₆ is an alkylene group having 1 to 20 carbon atoms that is unsubstituted or substituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms that is unsubstituted or substituted with a substituent; Or an arylene group having 5 to 20 carbon atoms substituted or unsubstituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms, R ₇ and R ₈ is independently of each other an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an alkylene group having 1 to 20 carbon atoms unsubstituted or substituted with an aryl group having 5 to 20 carbon atoms, R ₉ is hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; is a heterocyclic group having 3 to 30 carbon atoms, X is N, O or S atom, and when X is O or S, R ₉ is not present,

[Formula 1b]

In Formula 1b,

R ₁₀ is an alkylene group having 1 to 20 carbon atoms that is unsubstituted or substituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms that is unsubstituted or substituted with a substituent; Or an arylene group having 5 to 20 carbon atoms substituted or unsubstituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms,

R ₁₁ and R ₁₂ are each independently an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; It is a heterocyclic group having 3 to 30 carbon atoms.

In addition, the modifier may be, for example, a compound represented by the following formula (2).

[Formula 2]

In Formula 2, A ₁ and A ₂ are each independently an alkylene group having 1 to 20 carbon atoms, R ₂₅ to R ₂₈ are each independently an alkyl group having 1 to 20 carbon atoms, L ₁ and L ₂ and L ₃ and L ₄ is connected to each other to form a ring having 1 to 5 carbon atoms, wherein L ₁ and L ₂ and L ₃ and L ₄ are connected to each other and the formed ring is at least one selected from the group consisting of N, O, and S It contains 1 to 3 heteroatoms.

2nd synthetic rubber

In one embodiment of the present invention, the second synthetic rubber may be a butadiene-based rubber, specifically, a butadiene-based rubber in which the content of cis bonds in the polymer is 96% by weight or more.

In addition, the polybutadiene-based rubber may have a vinyl bond content of 50 wt% or less, and specifically, a cis bond content of 96 wt% or more and a vinyl content of 40 wt% or less in the polymer. Here, the cis bond and the vinyl bond are measured by Fourier transform infrared spectroscopy.

Meanwhile, the butadiene-based rubber may be prepared by polymerizing a conjugated diene-based monomer using a rare earth metal catalyst, a transition metal catalyst, or an alkali metal catalyst, wherein the conjugated diene-based monomer is as described above.

In addition, in one embodiment of the present invention, the butadiene-based rubber may use a commercially available butadiene-based rubber having the above-described physical properties, such as Nd-BR, Ni-BR, Co-BR or Li-BR.

filler

In one embodiment of the present invention, the filler is mixed with the rubber component to serve to improve the physical properties of the rubber composition, specifically, may be silica.

For example, the silica may be wet silica (hydrous silicic acid), dry silica (silicic anhydride), calcium silicate, aluminum silicate, or colloidal silica. Specifically, the effect of improving fracture properties and the compatible effect of wet grip properties may be the best wet silica.

On the other hand, the rubber composition according to an embodiment of the present invention may further include other rubber components as needed in addition to the above-mentioned rubber components, wherein the other rubber components are present in an amount of 90% by weight or less based on the total weight of the rubber composition. can be included as

The other rubber component may be, for example, natural rubber or synthetic rubber, and specific examples thereof include natural rubber (NR) including cis-1,4-polyisoprene; Modified natural rubbers such as epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber, which are modified or refined of the general natural rubber; Styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-) propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene) -co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, butyl rubber, halogenated butyl rubber, etc. have.

In addition, the rubber composition according to an embodiment of the present invention may be crosslinkable with sulfur, and thus may further include a vulcanizing agent.

The vulcanizing agent may be specifically sulfur powder, and may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the rubber component. It has an excellent effect.

In addition, in the rubber composition according to an embodiment of the present invention, when silica is used as the filler, a silane coupling agent for improving reinforcing and low heat generation may be used together, and as a specific example, the silane coupling agent is bis(3- Triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide , bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2 -Mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-trie Toxysilylpropylbenzolyltetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropylmethacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide , 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, or dimethoxymethylsilylpropylbenzothiazolyltetrasulfide, and any one of these or A mixture of two or more may be used. Preferably, in consideration of the reinforcing improvement effect, it may be bis(3-triethoxysilylpropyl)polysulfide or 3-trimethoxysilylpropylbenzothiazyltetrasulfide.

The rubber composition according to an embodiment of the present invention includes, in addition to the above components, various additives commonly used in the rubber industry, specifically, a vulcanization accelerator, process oil, plasticizer, anti-aging agent, anti-scorch agent, zinc white, It may further include stearic acid, a thermosetting resin, or a thermoplastic resin.

The vulcanization accelerator is, for example, a thiazole-based compound such as M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazyl sulfenamide), or DPG A guanidine-based compound such as (diphenylguanidine) may be used, and may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber component.

The process oil acts as a softener in the rubber composition, and may be, for example, a paraffinic, naphthenic, or aromatic compound. Naphthenic or paraffinic process oils may be used. The process oil may be included in an amount of 100 parts by weight or less based on 100 parts by weight of the rubber component, for example, and has an effect of preventing deterioration of the tensile strength and low heat generation (low fuel efficiency) of the vulcanized rubber within this range.

The antioxidant is, for example, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 6-ethoxy-2 ,2,4-trimethyl-1,2-dihydroquinoline, or a high-temperature condensate of diphenylamine and acetone, etc., may be used in an amount of 0.1 to 6 parts by weight based on 100 parts by weight of the rubber component.

The rubber composition according to an embodiment of the present invention can be obtained by kneading using a kneader such as a Banbury mixer, a roll, an internal mixer, etc. according to the compounding prescription, and has low heat generation and wear resistance by a vulcanization process after molding processing. This excellent rubber composition can be obtained.

Accordingly, the rubber composition may be used for each member of the tire, such as a tire tread, under tread, side wall, carcass coated rubber, belt coated rubber, bead filler, chaff, or bead coated rubber, vibration proof rubber, belt conveyor, hose, etc. It may be useful in the manufacture of various industrial rubber products of

In addition, the present invention provides a tire manufactured using the rubber composition.

The tire may include a tire or a tire tread.

Hereinafter, the present invention will be described in more detail by way of Examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

In Examples and Comparative Examples, parts by weight of the components other than the rubber component are shown based on 100 parts by weight of the rubber component used in each Example and Comparative Example.

In addition, in Examples and Comparative Examples, the same material was used for other components except for the rubber component, the coupling agent was bis(3-triethoxysilylpropyl)tetrasulfide (TESPT), the process oil was TDAE oil, and the vulcanization accelerator was CZ (N-cyclohexyl-2-benzothiazylsulfenamide) and DPG (diphenylguanidine) were used.

Example 1

Solution polymerization both ends modified styrene-butadiene rubber (styrene content 39% by weight, vinyl content 25% by weight, extender oil content 5% by weight) (MF3925, LG Chem) 63 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) %) 40 parts by weight, 70 parts by weight of silica, 5.6 parts by weight of a coupling agent, 27.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, A rubber composition was prepared by mixing 2.8 parts by weight of a vulcanization accelerator. At this time, the difference in solubility constant (Δδ) between the modified styrene-butadiene rubber at both ends of the solution polymerization and the rare earth catalyzed butadiene rubber was 0.89 (the solubility constant of the styrene-butadiene rubber at both ends of the solution polymerization = 18.06, the solubility of the rare earth catalyzed butadiene rubber constant = 17.17).

Example 2

Solution polymerization both ends modified styrene-butadiene rubber (styrene content 43% by weight, vinyl content 25% by weight, extender oil content 5% by weight) (MF4325, LG Chem) 63 parts by weight, rare-earth catalyzed butadiene rubber (cis bond content 96% by weight) %) 40 parts by weight, 70 parts by weight of silica, 5.6 parts by weight of a coupling agent, 27.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, A rubber composition was prepared by mixing 2.8 parts by weight of a vulcanization accelerator. At this time, the difference in solubility constant (Δδ) between the modified styrene-butadiene rubber at both ends of the solution polymerization and the rare earth catalyzed butadiene rubber was 1.00 (the solubility constant of the styrene-butadiene rubber at both ends of the solution polymerization = 18.17, the solubility of the rare earth catalyzed butadiene rubber constant = 17.17).

Example 3

Solution polymerization both ends modified styrene-butadiene rubber (styrene content 39% by weight, vinyl content 25% by weight, extender oil content 5% by weight) (MF3925, LG Chem) 84 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) %) 20 parts by weight, 100 parts by weight of silica, 8.0 parts by weight of a coupling agent, 36.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, A rubber composition was prepared by mixing 2.8 parts by weight of a vulcanization accelerator. At this time, the difference in solubility constant (Δδ) between the modified styrene-butadiene rubber at both ends of the solution polymerization and the rare earth catalyzed butadiene rubber was 0.89 (the solubility constant of the styrene-butadiene rubber at both ends of the solution polymerization = 18.06, the solubility of the rare earth catalyzed butadiene rubber constant = 17.17).

Comparative Example 1

Solution polymerization terminal styrene-butadiene rubber (styrene content 21% by weight, vinyl content 50% by weight, extender oil content 5% by weight) (F2150, LG Chem) 63 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) ) 40 parts by weight, 70 parts by weight of silica, 5.6 parts by weight of a coupling agent, 27.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, vulcanization A rubber composition was prepared by blending 2.8 parts by weight of an accelerator. At this time, the difference in solubility constant (Δδ) between the styrene-butadiene rubber at the end of solution polymerization and the rare earth catalyzed butadiene rubber was 0.23 (the solubility constant of the modified styrene-butadiene rubber at the end of solution polymerization = 17.40, the solubility of the rare earth catalyzed butadiene rubber) constant = 17.17).

Comparative Example 2

Solution polymerization terminal end styrene-butadiene rubber (styrene content 39% by weight, vinyl content 25% by weight, extender oil content 37.5% by weight) (F3925, LG Chem) 82.5 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) ) 40 parts by weight, 70 parts by weight of silica, 5.6 parts by weight of a coupling agent, 7.5 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, vulcanization A rubber composition was prepared by blending 2.8 parts by weight of an accelerator. At this time, the difference in solubility constant (Δδ) between the styrene-butadiene rubber at the end of solution polymerization and the rare earth catalyzed butadiene rubber was 0.89 (the solubility constant of the modified styrene-butadiene rubber at the end of solution polymerization = 18.06, the solubility of the rare earth catalyzed butadiene rubber) constant = 17.17).

Comparative Example 3

Solution polymerization terminal end styrene-butadiene rubber (styrene content 36% by weight, vinyl content 26% by weight, extender oil content 25% by weight) (F3626Y, LG Chem) 75 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) ) 40 parts by weight, 70 parts by weight of silica, 5.6 parts by weight of a coupling agent, 15.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, vulcanization A rubber composition was prepared by blending 2.8 parts by weight of an accelerator. At this time, the solubility constant difference (Δδ) between the solution polymerization styrene-butadiene rubber and the rare earth catalyzed butadiene rubber was 0.80 (the solubility constant of the styrene-butadiene rubber at the end of solution polymerization = 17.97, the solubility constant of the rare earth catalyzed butadiene rubber = 17.17 ).

Comparative Example 4

Solution polymerization terminal end styrene-butadiene rubber (styrene content 21% by weight, vinyl content 50% by weight, extender oil content 5% by weight) (F2150, LG Chem) 84 parts by weight, rare earth catalyzed butadiene rubber (cis bond content 96% by weight) ) 20 parts by weight, 100 parts by weight of silica, 8.0 parts by weight of a coupling agent, 36.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, 1.5 parts by weight of sulfur powder, vulcanization A rubber composition was prepared by blending 2.8 parts by weight of an accelerator. At this time, the difference in solubility constant (Δδ) between the styrene-butadiene rubber at the end of solution polymerization and the rare earth catalyzed butadiene rubber was 0.23 (the solubility constant of the modified styrene-butadiene rubber at the end of solution polymerization = 17.40, the solubility of the rare earth catalyzed butadiene rubber) constant = 17.17).

Comparative Example 5

Solution polymerization terminal end styrene-butadiene rubber (styrene content 21 wt%, vinyl content 50 wt%, extender oil content 5 wt%) (F2150, LG Chem) 105 parts by weight, silica 100 parts by weight, coupling agent 8.0 parts by weight, process A rubber composition was prepared by mixing 35.0 parts by weight of oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid, and 1.5 parts by weight of sulfur powder and 2.8 parts by weight of a vulcanization accelerator.

Comparative Example 6

Solution polymerization both ends modified styrene-butadiene rubber (styrene content 39% by weight, vinyl content 25% by weight, extender oil content 5% by weight) (MF3925, LG Chem) 105 parts by weight, silica 100 parts by weight, coupling agent 8.0 parts by weight, A rubber composition was prepared by mixing 35.0 parts by weight of process oil, 3 parts by weight of zinc oxide, and 1 part by weight of stearic acid to prepare a first formulation, and 1.5 parts by weight of sulfur powder and 2.8 parts by weight of a vulcanization accelerator.

Experimental example

In order to compare and analyze the physical properties of each rubber composition prepared in Examples and Comparative Examples and molded articles prepared therefrom, tensile properties, abrasion resistance and viscoelastic properties were measured respectively, and the results are shown in Tables 1 and 2 below. In addition, the rubber components and other components used in the preparation of each rubber composition of the Examples and Comparative Examples and their respective contents are also shown in Tables 1 and 2 together.

1) Tensile properties

For tensile properties, each test piece was prepared according to the tensile test method of ASTM 412, and the tensile strength at the time of cutting the test piece and the tensile stress (300% modulus) at 300% elongation were measured. Specifically, the tensile properties were measured at room temperature at a speed of 50 cm/min using a Universal Test Machin 4204 (Instron Co., Ltd.) tensile tester.

2) Wear resistance

For the abrasion resistance of the rubber specimen prepared in the same manner as in the above tensile properties, a load of 10 N was applied to the rotating drum to which the abrasion paper was attached, using a DIN abrasion tester, and the rubber specimen was placed at a right angle to the rotational direction of the drum. After moving, the worn weight loss was measured, and the weight loss of Comparative Example 2 was indexed and expressed. The rotational speed of the drum is 40 rpm, and the total travel distance of the specimen at the completion of the test is 40 m. It indicates that the higher the index value of the loss weight, the better the abrasion resistance.

3) Viscoelastic properties

Viscoelastic properties were measured using a dynamic mechanical analyzer (ARES G2 by TA) to change the deformation at a frequency of 10 Hz and each measurement temperature (-100℃~80℃) in torsion mode to obtain G" (dynamic loss modulus, E") and tan δ was measured. The higher the index value of the low temperature 0°C tan δ, the better the wet road resistance (braking performance), and the higher the index value of the high temperature 60°C tan δ, the less the hysteresis loss and the better the low running resistance (fuel efficiency).

In addition, the temperature sweep test was performed through the dynamic mechanical analyzer to measure the change in G", and through this, the phase separation phenomenon due to the difference in compatibility between rubbers was confirmed.

4) TEM (Transmission Electron Microscopy) analysis

For TEM images, each rubber composition was made into thin slices by microtomming using a Titan G2 80-200 Field Emission Transmission Electron Microscope (TEI) and measured at a magnification of 20K to 200K.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 first synthetic rubber F2150 63 - - - - F3925 - 82.5 - - - F3626Y - - 75 - - MF3925 - - - 63 - MF4325 - - - - 63 2nd synthetic rubber CB24 40 40 40 40 40 Solubility Constant 0.23 0.89 0.80 0.89 1.00 silica 70 70 70 70 70 coupling agent 5.6 5.6 5.6 5.6 5.6 process oil 27.0 7.5 15.0 27.0 27.0 zinc oxide 3 3 3 3 3 stearic acid One One One One One sulfur powder 1.5 1.5 1.5 1.5 1.5 vulcanization accelerator 2.8 2.8 2.8 2.8 2.8 Tensile properties 300% modulus 100 105 102 104 105 Elongation (%) 100 109 103 113 110 wear resistance 100 101 103 110 109 viscoelastic tan δ@0℃ 100 104 95 122 125 tan δ@60℃ 100 82 85 108 107

In Table 1, the tensile properties, abrasion resistance, and viscoelasticity result values of Examples 1, 2, Comparative Example 2 and Comparative Example 3 are indexed based on the measured values of Comparative Example 1. As shown in Table 1, it was confirmed that Examples 1 and 2 according to an embodiment of the present invention were significantly superior in tensile properties and viscoelastic properties compared to Comparative Examples 1 to 3 while improving abrasion resistance.

Specifically, Examples 1 and 2 showed excellent tensile properties and viscoelastic properties while significantly improving abrasion resistance, while Comparative Examples 1 and 3 including heterogeneous synthetic rubbers, but having a solubility constant difference of 0.82 or less between the two synthetic rubbers In the case of , it was confirmed that the tensile properties and viscoelastic properties were significantly reduced, and the abrasion resistance was also significantly reduced.

In addition, as shown in FIG. 1 , it can be seen that Examples 1 and 2 have two inflection points, but Comparative Examples 1 and 3 have one inflection point. Here, the inflection point is usually determined as the glass transition temperature, and therefore, the two inflection points indicate that there are two glass transition temperatures. That is, in the case of Examples 1 and 2, phase separation between the two synthetic rubbers is controlled by adjusting the solubility constant difference between the two synthetic rubbers to a specific range to adjust the compatibility so that each rubber component in the rubber composition is not mixed in a completely uniform state. Due to this, two glass transition temperatures can be exhibited, and in Comparative Examples 1 and 3, the difference in solubility constant between the two synthetic rubbers is small, so that each rubber component in the rubber composition is mixed in a completely uniform state to have one phase. It can be seen that it represents one glass transition temperature. This can also be confirmed through the TEM image of FIG. 2 , and specifically, it can be confirmed that the phase separation phenomenon appears clearly in Examples 1 and 2 .

Through the above results, in the case of Examples 1 and 2, by adjusting the solubility constant difference between the two synthetic rubbers over a specific range, the compatibility is adjusted so that each rubber component in the rubber composition is not mixed in a completely uniform state. While the effect expressed in each synthetic rubber is maintained due to the phase separation between the two synthetic rubbers, in Comparative Examples 1 and 3, the difference in solubility constant between the two synthetic rubbers is small, so that each rubber component in the rubber composition is mixed in a completely uniform state. As a result, it can be confirmed that the effect expressed in each of the synthetic rubbers cannot be maintained.

In addition, in Comparative Example 3, including two synthetic rubbers, but by adjusting the difference in solubility constant within the range presented in the present invention, the tensile properties were similar to those of Example 1, but it was confirmed that the abrasion resistance and viscoelastic properties were significantly reduced. did.

division Comparative Example 4 Comparative Example 5 Comparative Example 6 Example 3 first synthetic rubber F2150 84 105 - MF3925 - - 105 84 2nd synthetic rubber CB24 20 - - 20 Solubility Constant 0.23 - - 0.89 silica 100 100 100 100 coupling agent 8.0 8.0 8.0 8.0 process oil 36.0 35.0 35.0 36.0 zinc oxide 3 3 3 3 stearic acid One One One One sulfur powder 1.5 1.5 1.5 1.5 vulcanization accelerator 2.8 2.8 2.8 2.8 Tensile properties 300% modulus 100 117 124 105 Elongation (%) 100 81 86 105 wear resistance 100 77 87 103 viscoelastic tan δ@0℃ 100 143 197 142 tan δ@60℃ 100 101 126 111

In Table 2, the tensile properties, abrasion resistance, and viscoelasticity result values of Example 3, Comparative Examples 5 and 6 are indexed based on the measured values of Comparative Example 4 and are shown.

As shown in Table 2, it was confirmed that Example 3 according to an embodiment of the present invention has excellent tensile properties and significantly higher viscoelastic properties while improving wear resistance compared to Comparative Example 4.

In addition, as shown in FIG. 3 , it can be seen that Example 3 has two inflection points indicating the glass transition temperature, but Comparative Example 4 has one inflection point. In this case, Example 3 and Comparative Example 4 increased the ratio of the first synthetic rubber and silica and decreased the ratio of the second synthetic rubber compared to Example 1 and Comparative Example 1, respectively. Example 3 according to an embodiment of the two synthetic rubbers can exhibit two glass transition temperatures due to phase separation between the two synthetic rubbers by controlling the solubility constant difference between the two synthetic rubbers over a specific range to control the compatibility, and Comparative Example 4 In the case of , it can be confirmed that the difference in solubility constant between the two synthetic rubbers is small, indicating one glass transition temperature by having one phase. In addition, in the case of Comparative Examples 5 and 6, including one rubber component, it may have only one phase, which can be confirmed from the fact that there is only one inflection point in FIG. 3 . This can also be confirmed through the TEM image of FIG. 4 , and specifically, in the case of Example 3, it can be confirmed that the phase separation phenomenon appears clearly. In addition, Comparative Examples 5 and 6 showed excellent viscoelastic properties, but due to the absence of a second synthetic rubber having a relatively low glass transition temperature, the glass transition temperature of the rubber composition was increased, and thus the abrasion resistance was significantly lowered. that can be checked

Claims (8)

With respect to 100 parts by weight of the rubber component comprising the first synthetic rubber and the second synthetic rubber,
30 parts by weight to 90 parts by weight of a first synthetic rubber;
10 parts by weight to 70 parts by weight of a second synthetic rubber; and
30 to 200 parts by weight of a filler,
The first synthetic rubber and the second synthetic rubber are different from each other by a solubility constant of more than 0.82,
The first synthetic rubber has a styrene content of 38 wt% or more and 55 wt% or less, and is a solution-polymerized conjugated diene-based rubber modified at both ends with functional groups bonded to both ends,
The second synthetic rubber is a rubber composition wherein the content of cis bonds in the polymer is a butadiene-based rubber of 96% by weight or more.
The method according to claim 1,
The first synthetic rubber and the second synthetic rubber have a solubility constant greater than 0.82 and a difference of 1.05 or less.
delete The method according to claim 1,
The rubber composition of the both ends of the modified solution polymerization conjugated diene-based rubber having an extender oil content of greater than 0% by weight and 37.5% by weight or less.
delete The method according to claim 1,
The rubber composition is that the filler is silica.
The method according to claim 1,
The rubber composition is a rubber composition comprising a vulcanizing agent.
A tire manufactured using the rubber composition according to claim 1.

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